Hypodermic needles of this type are found on the market. Fixing them on the tip of an injection instrument is easier and faster because it is no longer necessary to screw the needle on, simple axial pressure sufficing to make the complementary connectors engage with each other. Theoretically separation by axial traction should also be possible but the lack of purchase makes this operation difficult for most people, and therefore it is effected in the traditional manner by unscrewing.
Given that in the case of chronic disorders requiring the daily injection of medical substances it is frequently the patient who must perform self-injection making it easier to handle injection needles meets a need, especially for the purpose of facilitating their safe removal, disposal or storage.
International publication WO 92/13585 (Aug. 20, 1992) describes a needle container comprising a conical housing. Prior to use, the needle is held by frictional forces at the open end of the conical housing. After use of the needle, the user can re-insert the needle into the conical housing, pushing the needle below elastic tabs at the open end of the conical housing. The resilient tabs snap back after the needle is fully inserted, preventing the needle from being withdrawn.
EP 0 364 839 discloses a syringe for medical use of the disposable type provided with a hollow cap that can be super-imposed to the needle to protect it after carrying out the injection. Close to the opening of the cap cavity, members are provided that firmly engage the collar of the needle when it is forced into the cap cavity.
In all of the prior art cases, when the needle is fixed at the outlet end of the syringe, the user is no longer protected from injury by the needle. Several injection devices have been proposed to obviate this inconvenience and comprise to this end a mechanism for effecting the injection, which is movable by a cocking means counter to the force of a spring into a cocking position, from which it can be released to effect an injection process, so as to act upon a piston containing fluid to be injected.
A device of this type is disclosed for example in EP 0 359 761. The housing of this device is approximately the shape of an oversize fountain pen, and the injection needle is inside the device as long as injection process is not being performed. The injection device has a mechanism used to effect the injection process, which mechanism can be moved by means of a cocking element counter to the force of a spring into a cocked position from which it can be released in order to effect an injection process. This mechanism moves the hypodermic needle axially so that it protrudes from the forward end of the housing of the device which is put into contact with the skin of the patient so that it is inserted through the skin and the liquid is injected.
With such a device, except during the injection process, the needle is inside the cylindrical barrel of the injection device, so that the user cannot see the precise position of the needle to be introduced into the opening of the housing in which the needle has to be separated from the injection device, since it is hidden from sight by the cylindrical barrel of the injection device.
The purpose of the present invention is to make the disposal of the used needles easier.